Incised pebbles found at the mid-Holocene, Middle Preceramic period Ostra Base Camp site on the Peruvian north coast demonstrate long-distance links to coastal Ecuador, 700 km to the north. The artifacts belong to a northwestern Andean pebble-figurine tradition associated with the tropical coast. Environmental indicators at the Ostra site show a warm-water lagoonal environment, unlike the modern cold-water conditions of northwestern Peru but similar to modern Ecuador. The Ostra site dates between ca. 5500 and 6250 B.P. (3550 and 4300 B.C.), during a hiatus in the coastal Ecuadorian record, so the link to Ecuador provides the earliest evidence of long-distance cultural interaction between these regions. Until contemporary sites are found in Ecuador, the Ostra Base Camp site provides our only example for this time of tropical coastal cultures of the northwestern Andean interaction sphere.

Lathrap, D.1973The Antiquity and Importance of Long-Distance Trade Relationships in the Moist Tropics of Andean South America. World Archaeology5:170–186.

Lathrap, D.1974The Moist Tropics, the Arid Lands, and the Appearance of Great Art Styles in the New World. In Art and Environment in Native America, edited by M. E. King and I. R. Traylor, Jr., pp. 115–158. Special Publications No. 7. The Museum, Texas Tech University, Lubbock.

Llagostera, A.1992Early Occupations and the Emergence of Fishermen on the Pacific Coast of South America. Andean Past3:87–109.

Lutaenko, K. A.1993Climatic Optimum during the Holocene and the Distribution of Warm-Water Mollusks in the Sea of Japan. Palaeogeography, Palaeoclimatology, Palaeoecology102:273–281.

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Richardson, J. B.1987The Chronology and Affiliations of the Ceramic Periods of the Departments of Piura and Tumbes, Northwest Peru. Paper presented at the 51st Annual Meeting of the Society for American Archaeology, Toronto.